Summary Benzaldehyde is also called benzoic aldehyde&period; Benzaldehyde is an organic compound&comma; and is synthetized by the way that the hydrogen of benzene is substituted by aldehyde&period; It is the most simple&comma; and also the most commonly used industrial aromatic aldehyde&period; It is a colorless liquid at room temperature and has a special almond odor&period; Benzaldehyde is a compound that aldehyde is directly linked to the phenyl group&comma; because it has a similar bitter almond flavor&period; Benzaldehyde widely exists in plant&comma; especially in the Rosaceae plants&period; It is mainly in the form of glycosides in plant stem bark&comma; leaves or seeds&comma; such as amygdalin&comma; bitter almond&comma; cherry&comma; laurel&comma; peach&period; Benzaldehyde is naturally in bitter almond oil&comma; patchouli oil&comma; hyacinth oil&comma; cananga oil&period; The compound is also in the nutlets and nuts&comma; and exists in the form of Amygdalin&comma; which is combination of glycosides&period; The chemical properties of Benzaldehyde is similar to that of aliphatic aldehydes&comma; but It is also different&period; Benzaldehyde cannot reduce fehling reagent&period; When the reducing fat is used to reduce the benzaldehyde&comma; the main products are benzene methanol&comma; four substituted for the ortho - glycol and two - phenyl ethylene glycol&period; In the presence of potassium cyanide&comma; two molecules of benzaldehyde form benzoin by acceptance the hydrogen atom&period; The substitution reaction in aromatic nucleus of benzaldehyde is mainly the meta-position product&period; For example&comma; the main product is the m-nitrobenzaldehyde &comma; when benzaldehyde is nitrated&period; Today&comma; the benzaldehyde is prepared by different methods&period;